Ironically, my own field tests with a variety of sites (from small ones to the multi-million page Fortune 500 variety) would suggest that Mr. Cutts' assertion is false, but I think that this article and his comments are still worth mentioning.Perhaps there is a bit of a dropoff with the 301, but maybe it's so minimal (think trace amounts of decay/loss) that it has no discernable impact on existing/future rankings.